I find Sloman's ideas a welcome expansion on the social function of mood.
2. Sloman's idea about the adaptive value of internalizing "the badness that was previously perceived in the other individual" is novel and intriguing. I had never seen how this particular bit of human nature might be adaptive, but his suggestion makes sense. Going further along similar lines, Hartung (1988) has suggested that low self-esteem may often be a deception (and self-deception) that allows one to keep a position in the hierarchy without threatening the higher-ups. Sloman's ideas about high mood I find a bit optimistic, in that hypomanics aren't particularly ready, in my experience, to accept the submissive gesture of another. I also have some difficulty with the idea that mood helps people find their place in the hierarchy. Repeated failure in a high position sets off low mood and a slide in the hierarchy, and this might well benefit the group, but it is hard for me to see how such individuals will reproduce more for having given up that position. Those lower in rank will be better served by frustration that motivates them to challenge others, rather than by low mood. All in all, I find Sloman's ideas a welcome expansion on the social function of mood.
Hartung J. (1988) Deceiving down. In: Lockard JS, Paulhus D, ed. Self Deception: An Adaptive Mechanism? Englewood Cliffs, NJ: Prentice Hall, 170-185.